December 6, 2013 7:03 pm

Magnum Photos captures tidal power

The second in our series of essays from Magnum Photos on British industry examines the potential of tidal power as a future source of renewable energy

The Pelamis P2 wave machine is named after a kind of sea snake. But when I first encountered one of these red-and-yellow 180m-long monsters riding the north Atlantic swell off the rocky western coast of Orkney, it looked to me more like a strange new species of amphibious high-speed train.

The P2 is a substantial piece of industrial kit: a string of five 4m-wide steel tubes that weighs 1,350 tonnes when fully ballasted. It is also the embodiment of a long-cherished, often-frustrated dream: to capture the energy of the waves that endlessly pummel our shores and make it our own.

This P2, one of a handful of competing wave machines being tested at Orkney’s European Marine Energy Centre, is already feeding electricity to the local grid. Power output is small – just a few 100 kilowatts, acknowledges Richard Yemm, founder and CEO of Pelamis Wave Power, one of a number of companies testing equipment in the area. But he is confident that in the next few years commercial arrays of Pelamis machines will be generating many megawatts – and that eventually waves could account for perhaps one-fifth of UK electricity demand. “The potential output is prodigious – many, many gigawatts of power,” he says.

Out on the waters off Emec’s wave test site at Billia Croo, it is easy to believe in the scale of the resource. Facing the full force of the ocean, waves here average between 2m and 3m, and can reach as high as 17m. Even on a calm day, our boat was rocking wildly and the P2 was in unceasing movement.

Yet for decades, wave power has been the source of disappointment. Away from the beach, waves are fiendishly complex things, making it difficult to capture the energy they contain. And salt water and storms make for an unforgiving operating environment.

Pelamis is no stranger to setbacks. The Edinburgh-based company pioneered the world’s first commercial wave project off northern Portugal in 2008. But within months the three initial machines had to be towed back to port for repairs, and the project was abandoned when the Portuguese utility’s parent company collapsed.

Just this year, the German company Eon walked away from its co-operation with Pelamis in Orkney, blaming the slow progress of wave technology development. Pelamis insists it is still on track and that the technical problems suffered in Portugal have been fully resolved in the P2 machines at Orkney.

There is no doubting the cleverness of the Pelamis design. The towable P2 is tethered to an underwater power cable, with little need for workers to linger at sea. Its vulnerable machinery is tucked safely within its watertight steel hull, as I discovered when I climbed into the belly of one of the machines while it was tied up in Lyness harbour on the Orkney island of Hoy.

The P2’s long shape means it naturally faces into the prevailing waves. These lift and lower the machine’s separate sections as they pass, flexing their connecting joints and compressing hydraulic cylinders that pump fluid into high pressure accumulators. The fluid then provides smooth and continuous electricity generation.

In a Lyness harbour shed, Pelamis staff watch real-time data pour in from the machine working offshore. This data, accumulated over the more than 10,000 grid-connected hours at sea racked up by the two P2 machines, will be crucial in persuading cautious utilities that the technology is ready, says Yemm. “We are really close.”

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Mure Dickie is the FT’s Scotland correspondent. ‘Open for Business’ is a collaboration between Multistory and Magnum Photos, funded by Arts Council England and nine UK cultural institutions.

A nationwide touring exhibition opens at the National Media Museum, Bradford, in January 2014. www.openforbusiness.uk.com

Magnum photographers in the Black Country

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